Dwayne Johnson felt like he was in a "bubble" when he battled with depression.
The Furious 7 star admits he struggled to relate to anyone but over time learned to realise he wasn't alone.
He said: "I found that with depression one of the most important things you could realise is that you're not alone.
"You're not the first to go through it, you're not going to be the last to go through it and often you feel like you're alone and you feel like it's only you and you're in your bubble. I wish I had someone at that time who could just pull me aside and [say], 'Hey, it's going to be okay.'"
The 43-year-old actor also made a public plea to those suffering with the illness to "hold on to that fundamental quality of faith".